With the introduction of the Chromium-based Edge browser on the Xbox Series X|S, gamers will have access to a ton of new features on the platform. Apart from online web-based applications like WhatsApp, Telegram, Skype, and Discord, there’s also the possibility of streaming services other than xCloud.
The primary contender in this respect is NVIDIA’s GeForce NOW streaming service which allows gamers to stream the latest titles (most of them anyway) on just about any device with a decent internet connection. At present, the streaming service is limited to 1080p 60 FPS, so you’ll be cutting corners with respect to visual quality especially considering that the next-gen consoles were specially marketed for 4K gaming, but it should be okay if you have the Series S.
Apart from GeForce NOW, other streaming services such as Google Stadia, Amazon Luna should also (technically) work on the Series consoles, but it’s unclear whether Microsoft will put any blocks in place to prevent the use of these services.